Macrophage cells provide the human body with the ability to clear out or to remove dead or decaying cells. Their primary mechanism for accomplishing this task is to engulf and then to digest cellular debris and pathogens, and they can act as either stationary or mobile cells, and stimulate lymphocytes and other immune cells to respond to pathogens. In many circumstances this is a highly desirable action.
However, macrophages can also target materials in the body that the host organism would prefer were left in place. For example, macrophage cells have been indicated as the major mechanism through which inflammatory cytokines are produced in rheumatic arthritis and in turn can lead to the deleterious removal of cartilage. Macrophages have also been implicated in the immunologically distinct condition of osteoarthritis.
To date interventions for conditions such as rheumatoid arthritis and osteoarthritis have focused on treating the resulting inflammation and pain but not the upstream causes of these symptoms. Thus, although this may provide some relief from the symptoms of inflammation and pain; however, the underlying condition remains a problem. Accordingly, there is a need to provide effective treatments to prevent undesirable macrophage recruitment, which in turn may prevent the production of substances that cause the problems such as the inflammatory cytokines.